In applications of high current, low voltage microprocessors, the power performance, especially the transient response is typical. Adaptive voltage position (AVP) control is widely used to reduce voltage deviations of the output voltage (i.e., the power supply of microprocessors) during the load step to insure the system stability.
The basic principle of traditional AVP control is shown in FIG. 1. An output voltage VO decreases linearly from a voltage value V1 to a voltage value V2, as an output current IO (i.e. load current) increases from a minimum value (e.g., from zero) to a maximum load point Imax, wherein V1 may be a reference voltage set according to a voltage identification code (VID) from a processor load.
With fast development of the microprocessor, power supply with higher voltage level is needed. The output voltage at full load may be very low, which may be close to a lowest threshold of the CPU operational voltage, if traditional AVP control is adopted. Thus, an improved voltage regulator with better output voltage control is in high demand.